A high-speed communications network typically includes network devices, such as routers and bridges, used for facilitating delivery of data packets from source devices to destination devices. Information pertaining to the transfer of packets through the network is usually embedded within each of the packets. Each packet traveling through the network, e.g., the internet and/or ethernet, can typically be handled independently from other packets in the packet stream or traffic. For example, each router may include routing, switching, and/or bridging engines to process incoming packets and determine where those incoming packets should be forwarded.
In recent years, Wi-Fi/WiMax technologies have been extensively developed for user devices to access a wired backbone network such as the internet. Typically, Wi-Fi routers have been connected to each other to form a mesh network of routers to repeat and carry data packets and other data traffic throughout the mesh network. Each router generally stores and forwards each data packet before transmitting or retransmitting the data packet to the rest of the mesh network. Thus, a data packet may travel multiple hops from one node to another node in the network. Due to each router having to store the entire data packet before retransmitting, the latency increases as the number of hops increases. Thereby, the connection performance of the mesh network is severely degraded. Wireless link quality is also prone to interference from the surrounding environment causing the link quality to be time varying and unstable.
FIG. 1 illustrates a graph of various data link speeds with the effect of latency delay in a mesh network using store and forward packet repeating. For a short internet protocol (“IP”) packet, there are about 20,000 bits to a packet. TCP/IP starts out with a window of 10 packets that is transmitted before the transmission stops and waits for an acknowledgment packet to continue with the transmission. With lower data transmission speeds of 3 Mbps or less, latency of 10 msec has little effect on the effective throughput.
However, as transmission speed increases, packets can travel at a faster rate causing latency to be a predominate consideration. For a 50 Mbps link speed having 10 msec latency, there is about twenty store and forward hops, where the effective throughput calculates to about 16 Mbps (about 40 Mbps less than the maximum link speed). Thus, as the number of nodes within a mesh network cluster increases, the number of hops also increases causing the effective throughput to decrease dramatically due to the latency. Therefore, the effective throughput can be much lower than the maximum link speed.
For a Wi-Fi mesh network communicating at 54 Mbps (e.g., 802.11g speeds), the limit on the number of hops from nodes to other nodes should be limited to 40 hops to prevent latency issues. For a large number of hops for a mesh network (e.g., a city, a neighborhood, or an office/campus deployment which can be in the 1,000's of nodes), the effective throughput is too low to support most applications, such as web cameras and web browsing internet access. For instance for multi-gigabit access speeds (e.g., 2 Gbps), a 10 msec of latency would be equivalent to 500 hops with an effective throughput of 24 Mbps. In effect, the multi-gigabit link would be crippled by the enormous latency due to the traditional packet store and forward methods.
Therefore, there exists a need for methods, systems, and apparatuses for a communications network that has improved range, greater reliability, availability, and reduced latency.